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Constraint on direction during linear buckling analysis?
Posted 10 mag 2023, 07:51 GMT-4 Studies & Solvers, Structural Mechanics 2 Replies
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Hello,
I am relatively new to comsol, and I have a question about the critical load factor in linear buckling. I understand that the CLF is the value of λ at which the structure becomes unstable, and that by studying more modes of buckling I can calculate the CLF for modes that occur with more force.
However, is it possible to constrain the buckling analysis to return only positive values of the CLF? I am studying buckling of a structure during tensile stretching, and I am only interested in buckling that I know will happen above a certain stretching force. As of now, the linear buckling analysis returns only negative values of the CLF (compression), even when I analyze many modes.
Thank you very much for any insight you can share,
Jane
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This is a very good question. We have actually recently prepared an example of something similar to your case, which will appear in the next release.
The thing to do is to make the eigenvalue solver look in the right direction. As a default it will find the eigenvalues with the smallest absolute value.
Go to the Eigenvalue Solver node in the study sequence. There, you set Search for eigenvalues around to a suitable positive value based on the expected critical load factor for the case you are interested in. Also, set the Eigenvalue search method around shift to Larger real part.
-------------------Henrik Sönnerlind
COMSOL
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Many thanks for your input! I will give this a try. I also look forward to seeing the example in the next release.
Jane